A lob bomb (known officially as an improvised rocket-assisted mortar, improvised rocket-assisted munition, or IRAM) is a rocket-fired improvised explosive device made from a large metal canister (usually a propane gas tank that has been drained of its contents and filled with explosives, scrap metal, and ball bearings), which has been used by insurgents during the Iraq War since late 2007. The weapon is essentially an airborne version of an improvised explosive device.
Lob bombs are propelled by 107 mm rockets and launched, several at a time, from the backs of small trucks where they are arranged in rows, sometimes by remote control (using a signal from either a cell phone, cordless phone, command wire, or other form of remote control device). They are typically launched in an arced trajectory, which enables them to be aimed over walls that enclose U.S. bases and other military facilities, in a similar manner to a conventional mortar. The weapon is believed to be highly inaccurate, and unofficial estimates place the range of lob bombs used so far as being between 50 and 150 yards (approx. 45 to 140 m).
According to U.S. military officials, lob bombs are designed to cause "catastrophic damage," and have the ability to kill "scores of soldiers" at once, more than conventional improvised explosive devices. As of July 12, 2008, out of 11 lob bomb attacks on American bases, three U.S. soldiers had been killed and 15 had been wounded, all three deaths occurring in an April 28, 2008 attack on a U.S. base in eastern Baghdad.
So far, the weapon has only been encountered in Baghdad, where it appears to be used by Shiite militias, whose superior ability to conceal forensic evidence about their identity has been acknowledged by the U.S. military. The U.S. military has found that the rockets used to propel the lob bombs have been produced in Iran, Russia, and China. One media report  indicates such a munition may have been used by the Taliban to bring down a Chinook helicopter in Afghanistan on August 6, 2011.
Such devices were first described in the international media in July 2008. In July 2008 Major General Jeffery Hammond, the commander of the 4th Infantry Division and commander of U.S. forces in Baghdad, called the lob bomb "the greatest threat right now that we face."
The type of improvised launch system and rocket is not new to warfare. The Provisional Irish Republican Army developed a similar system during the Troubles. It was used in the February 1991 attack on 10 Downing Street, the London office and home of the British prime minister.
- "'Lob Bombs' Big Worry for US in Iraq - TIME". Time.
- VOA News - Insurgents Using New Homemade Rocket Weapon in Iraq
- Democracy Now! | Stop-Loss: A Look at the US Military Policy that Creates a "Backdoor Draft" to Force Soldiers to Continue Service
- Burns, Robert (July 12, 2008). "AP: 'Lob bombs' biggest worry for US in Baghdad". Fox News. Retrieved March 10, 2011.
- Defense Review - Baghdad: Improvised Rocket-Assisted Munitions (IRAMs) Arrays Can Kill over Walls
- Lob Bomb
- Axe, David (8 August 2011). "Did a New Taliban Weapon Kill a Chopper Full of Navy SEALs?". Wired.com Danger Room blog. Retrieved 8 August 2011.
- Story from Democracy Now! program, July 11, 2008